Hello, Joey!
Our family travels to Walt Disney World several times a year, and we've noticed that some items remain the same--most often the classics--while others are introduced from time to time.
The iconic play sets, such as Cinderella Castle and Disney's Hollywood Studios Sorcerer's Hat are classics that are most often available in the parks, as well as at
Disney Store.com. New additions to these classics are available, too, such as Space Mountain Play Set. Other toy items are also updated to reflect seasonal or celebratory events or even new characters. Some examples include the Hot Wheels 40th Anniversary Walt Disney World Semi Truck, Disney Racers TRON: Legacy Sam Flynn Die Cast Car and Tangled merchandise.
Other new ventures include Duffy the Disney Bear, Vinylmation figures as well as new options at Downtown Disney's Ridemakerz, where you can build your own radio controlled car or truck (this one is located inside Team Mickey Athletic Club at Downtown Disney Marketplace.)
Garments, on the other hand, change not only from year to year, but also seasonally. This past month, for example, I just picked up a T-shirt in Frontierland, which I'd never seen previously. (It's a drawing of my son's favorite Walt Disney World snack...a turkey leg!)
In short, merchandise is always changing, often updating and varies from park to park. If you are looking for an old favorite, however, you might be in luck. Just ask a Cast Member to either show you what's new or help guide you to a particular item you've seen there in the past. They are always so willing to help guests!
I hope that you find this helpful! Should you need any additional assistance, please send your questions our way!